EP0660077A2 - Méthode pour déterminer l'épaisseur d'une couche - Google Patents

Méthode pour déterminer l'épaisseur d'une couche Download PDF

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Publication number
EP0660077A2
EP0660077A2 EP94309599A EP94309599A EP0660077A2 EP 0660077 A2 EP0660077 A2 EP 0660077A2 EP 94309599 A EP94309599 A EP 94309599A EP 94309599 A EP94309599 A EP 94309599A EP 0660077 A2 EP0660077 A2 EP 0660077A2
Authority
EP
European Patent Office
Prior art keywords
light
thickness
coating
reflected
incident light
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP94309599A
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German (de)
English (en)
Other versions
EP0660077A3 (fr
Inventor
Spencer Edwin Taylor
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
BP PLC
Original Assignee
BP Australia Pty Ltd
BP PLC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by BP Australia Pty Ltd, BP PLC filed Critical BP Australia Pty Ltd
Publication of EP0660077A2 publication Critical patent/EP0660077A2/fr
Publication of EP0660077A3 publication Critical patent/EP0660077A3/fr
Withdrawn legal-status Critical Current

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B11/00—Measuring arrangements characterised by the use of optical techniques
    • G01B11/02—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness
    • G01B11/06—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness for measuring thickness ; e.g. of sheet material
    • G01B11/0616—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness for measuring thickness ; e.g. of sheet material of coating
    • G01B11/0641—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness for measuring thickness ; e.g. of sheet material of coating with measurement of polarization
    • G01B11/065—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness for measuring thickness ; e.g. of sheet material of coating with measurement of polarization using one or more discrete wavelengths

Definitions

  • the present invention relates to a method of determining the thickness of a coating, in particular the thickness of aviation fuel coatings.
  • JFTOT Jet Fuel Thermal Oxidation Test
  • TDR Tube Deposit Rater
  • US Patent 5293218 discloses a method for determining the amount of residue of jet fuel as a film on JFTOT tubes. The method requires the use of interferometry where the tube is contacted with a light. The degree of reflected light from the tube is measured and correlated with coating thickness. Whilst interferometric determination provides a sensitive tool for thick films such as 70 microns or more, this method cannot be used to determine coatings of less than 70 microns.
  • the present invention provides a method for determining the thickness of a coating on a coated substrate which comprises:
  • the present invention provides a non-destructive, sensitive method of determining the thickness of a deposit or coating on a substrate and is especially applicable to the determination of the thickness of aviation fuel on standard JFTOT tubes.
  • the method of the present invention uses ellipsometry and according to a further aspect of the present invention there is provided a device for measuring the thickness of a coating on a coated substrate which comprises:
  • the method of the present invention is not limited by the thickness of the coating on the substrate.
  • coatings having a thickness of from 0 to 600nm can be determined, preferably 0 to 250nm, especially 0 to 70nm.
  • the coated substrate is exposed to an incident light.
  • the light is monochromatic and may be obtained from a laser source.
  • the light may have a wavelength of from 500-1000nm, preferably 600-800, especially 600-750nm.
  • the preferred laser source is a HeNe laser emitting light at a wavelength of 632.8 nm. It is preferred that the laser is inclined at an angle to the vertical. Suitably, the angle is from 50 to 70Q.
  • the light is polarised prior to contact with the coated sample. Any suitable polarising filter well known to the person skilled in the art may be used for this purpose. It is preferred that as part of the polarising procedure, the incident beam is also passed through a quarterwave plate. Again, such plates will be well known in the art.
  • the incident light beam is made to contact with the coated substrate which may be accommodated in a suitable compartment.
  • the sample compartment may be adjustably mounted such that movement of the sample may be carried out to allow the sample to be positioned in the exact plane of the incident beam.
  • the sample compartment may suitably be adjusted in both vertical and horizontal directions.
  • the incident polarised beam is reflected from the coated substrate.
  • the reflected polarised light is detected and measured.
  • the reflected light is directed to an optical system which may comprise an analyser and a detector. It is preferred, although not essential, to use a constantly rotating analyser.
  • the analyser and detector are mounted on the same plane and held at the same angle to the vertical as the laser source and the polarising equipment.
  • the data obtained from the detector and analyser may suitably be analysed using appropriate computer software to enable calculation of the coating thickness.
  • Such software is commercially available and will be well known to the person skilled in the art.
  • a series of measurements be carried out along the surface of the coated substrate to provide an overall picture of the thickness of the coating.
  • the sample position may be adjusted at the end of each procedure.
  • the sample may be moved from between 10 and 200 microns, preferably from 20 to 150 microns. This procedure may be repeated until substantially all of the surface of the coated substrate has been analysed.
  • coated substrates using organic films produced from fatty acids and their heavy metal salt or any water-insoluble material may be used. Such layers may be produced using the Langmuir-Blodgett film deposition technique. Suitably, 5 to 151, preferably from 15 to 61 monolayers may be deposited and analysed according to the present invention. It is preferred that the substrates coated in this way are coated with "stepped" Langmuir-Blodgett layers to enable a range of known film thickness measurements to be made.
  • a laser (1) inclined at an angle of between 50 and 70Q to the vertical emits a beam (2) which is passed through a polarising filter (3) and a quarterwave plate (4) before impinging on the coated sample (5) which is able to move in the direction of the laser beam allowing profiling of the tube surface.
  • the polarised incident beam (2) On contact with the surface of the sample, the polarised incident beam (2) is reflected.
  • the reflected polarised beam (6) is analysed by an optical system comprising a detector (7) and an analyser (8) mounted on the same plane and held at the same angle to the vertical as the laser (1), the polarising filter (3) and the quarterwave plate (4).
  • the sample (5) is placed in a sample compartment.
  • the polarised incident beam (2) impinges on the coated sample (5) at a given position, eg at one end.
  • the reflected polarised light (6) is passed into the detector (7) and analyser (8) and the data computed using a computer.
  • the computer also controls the sample position which may be adjusted by a small distance determined by the resolution of the polarised incident light beam (2).
  • the light reflected from the new position is data logged and the process repeated over the length of the sample until the full region has been profiled.
  • the refractive index and film thickness are then calculated using computer software purchased from Plasmos and identified as Plasmos SDENG 3.67.
  • a model coated tube was prepared in the following way:-A monolayer of behenic acid (docosanoic acid, CH 3 (CH 2 ) 20 COOH) received from Hull University was spread on an aqueous subphase in a Langmuir trough. The subphase contained 0.125 g/i CdC1 2 .2.5H 2 0 to assist monolayer deposition and 0.53 g/i NH 4 CI to buffer the pH to approximately 5.7. Accurate control of the state of the monolayer was achieved by maintaining a constant surface pressure during deposition. Surface pressure was monitored using a filter paper Wilhelmy plate. The tube was moved longitudinally into and out of the aqueous subphase through the air-water interface at a controlled rate of between 0.5 and 2.5mm/minute.
  • the tube was initally immersed to the maximum depth before spreading a certain amount of the film material on the surface of the water from a suitable spreading solvent which was 40 f..ll of a solution containing 0.35 mg behenic acid dissolved in 10 ml of chloroform.
  • a suitable spreading solvent which was 40 f..ll of a solution containing 0.35 mg behenic acid dissolved in 10 ml of chloroform.
  • the vertical position of the tube in the subphase was controlled by a computer, allowing close monitoring of the deposition process.
  • the coated tubes prepared according to Example 1 were placed in the sample compartment and a monochromatic light of 632.8 nm wavelength from a HeNe laser was made to impinge on the sample at one end.
  • the incident beam was reflected from the sample surface and the state of polarisation of the reflected beam analysed by a constantly rotating analyser.
  • the information was fed into the purpose built software to allow computation of the refractive index and film thickness (Plasmos SDENG 3.67).
  • the procedure was repeated along the length of the sample.
  • the profiles obtained from each sample are given in Figure 2. The profiles obtained indicate coating thicknesses in agreement with that determined during the preparation.
  • Example 2 The procedure of Example 2 was repeated to determine the deposit film thickness profiles of a series of JFTOT tubes produced from a Merox fuel thermally stressed at a number of different temperatures ranging from 270 to 290°C. It can be seen from Figure 3 that the tube subjected to the highest temperature has the thickest deposit.
  • Example 3 The procedure of Example 3 was repeated to determine the deposit film thickness profiles of a series of JFTOT tubes produced from a Merox fuel run at different run times ranging from 75 to 150 minutes. It can be seen from Figure 4 that the coating thickness ranges from 20 to 120nm.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Length Measuring Devices By Optical Means (AREA)
EP94309599A 1993-12-23 1994-12-20 Méthode pour déterminer l'épaisseur d'une couche. Withdrawn EP0660077A3 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB939326247A GB9326247D0 (en) 1993-12-23 1993-12-23 Method of determining thickness of coating
GB9326247 1993-12-23

Publications (2)

Publication Number Publication Date
EP0660077A2 true EP0660077A2 (fr) 1995-06-28
EP0660077A3 EP0660077A3 (fr) 1996-11-20

Family

ID=10747066

Family Applications (1)

Application Number Title Priority Date Filing Date
EP94309599A Withdrawn EP0660077A3 (fr) 1993-12-23 1994-12-20 Méthode pour déterminer l'épaisseur d'une couche.

Country Status (2)

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EP (1) EP0660077A3 (fr)
GB (1) GB9326247D0 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7515253B2 (en) 2005-01-12 2009-04-07 Kla-Tencor Technologies Corporation System for measuring a sample with a layer containing a periodic diffracting structure
US7859659B2 (en) 1998-03-06 2010-12-28 Kla-Tencor Corporation Spectroscopic scatterometer system
US10234266B2 (en) 2014-11-24 2019-03-19 Abo Akademi (Abo Akademi University) Method for calibrating 3D imaging and system for 3D imaging
CN120293982A (zh) * 2025-03-04 2025-07-11 泸州川玻科技有限公司 一种玻璃瓶表面喷涂质量检测方法

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR960010675B1 (ko) * 1991-01-30 1996-08-07 니홍 고오강 가부시끼가이샤 일립서미터(ellipso meter) 및 이것을 이용한 도포두께 제어방법
DE4108329C2 (de) * 1991-03-14 1993-10-14 Plasmos Gmbh Prozesstechnik Verfahren zum Bestimmen von Materialparametern, nämlich Dicke, Brechungsindex und Absorptionskoeffizient, einzelner Schichten
US5293218A (en) * 1992-06-30 1994-03-08 The United States Of America As Represented By The Secretary Of The Navy Interferometric JFTOT tube deposit measuring device

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7859659B2 (en) 1998-03-06 2010-12-28 Kla-Tencor Corporation Spectroscopic scatterometer system
US7898661B2 (en) 1998-03-06 2011-03-01 Kla-Tencor Corporation Spectroscopic scatterometer system
US7515253B2 (en) 2005-01-12 2009-04-07 Kla-Tencor Technologies Corporation System for measuring a sample with a layer containing a periodic diffracting structure
US10234266B2 (en) 2014-11-24 2019-03-19 Abo Akademi (Abo Akademi University) Method for calibrating 3D imaging and system for 3D imaging
CN120293982A (zh) * 2025-03-04 2025-07-11 泸州川玻科技有限公司 一种玻璃瓶表面喷涂质量检测方法

Also Published As

Publication number Publication date
GB9326247D0 (en) 1994-02-23
EP0660077A3 (fr) 1996-11-20

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